The purpose is to determine the sensitivity of various acoustic measures to vocal pathology associated with laryngeal diseases/disorders indcluding laryngeal carcinoma, vocal polyps, vocal nodules and contact ulcers. Acoustic assessment procedures will provide an objective means of quantifying voice disorders or dysfunctions, and evaluating the effects of various treatments on vocal pathologies. A microprocessor has been developed for quantifying frequency perturbation (jitter) while a similar system has been developed to quantifying amplitude perturbation (shimmer). Both measurement techniques have improved resolution over previous methods of measurement, and provide indices of vocal function which are stable across normal adults with different fundamental frequencies.